Chemical enginering

The world of IT

Entertainment

My social views

Tuesday, December 11, 2012

2)Extract the zip file to c:\sphinx folder. You can find a file named
searchd.exe file in c:\sphinx\bin\ folder.

3)To install searchd.exe from command prompt follow the steps.

·Startàtype ‘cmd’ in the search box. Now shows cmd.exe in the program list right
click on it select run as administrator. Please note select run as
administrator is very important other vise it will show some errors. Now type

Thursday, December 6, 2012

The
continuous caustic fusion plant for making caustic soda flakes (100%c
concentrated NaOH).The feed solution containing not less than 30%
NaOH is evaporated to 50% in two evaporators & 9kg/cm2 steam.
The 50% caustic soda by2 is conc. To 98 to 99% in evaporator No. 3
using heat transfer slat heated in a furnace with furnace oil & hydrogen
gas. The heating medium contains 7% NaNO3, 50% KNO3 &
43% NaNO2. H2 used for heating is to minimize oil
consumption. The flakes then formed from the flakes is sent to packing section.

High efficiency heat transfer salt heating
system by the combustion of fuel oil & H2 gas.

One specially designed flaking machine to
process high concentrated caustic soda melt into flakes at low temp.

Two semi – automatic bagging scales to fill
hygroscopic NaOH flakes into open type bags at 50kg each (one is stand – by to
the other)

Instrument & control systems designed to
operate the process plant automatically

Specification
of feed solution

Feed source ex ion exchange membrane cells

Analysis (as is basis)

NaOHmin 30% w/w

NaClmax 0.005% wt

Na2Co3max………. ppm wt

NaClO3max………. ppm wtto be
specified

Fe2O3max………. ppm wt

Temp600C

Pressure at grade2.5 barg

Specification
of caustic soda solution

At outlet of caustic cooler HE – 4

NaOH 50%
w/w

Temp400C

Pressure at grade2-5 barg

Specification
of flakes

NaOH 99%
w/w total solids

Temp at outlet of bagging scale55-600C max

Thicknessapprox
0.8 – 1.2 mm

Bulk densityapprox
0.7 – 0.9 kg/dm3

Volumeapprox
0.3 – 1cm2

Specification
of chemicals

Sugar (As corrosion Inhibitor)

oQuality Food
grade, white, granulated

(in
bags, near area of usage)

Heat transfer salt

oComposition

KNO3:50% w/w

NaNO2:43% w/w

NaNO3:7% w/w

Sulphur:max. 0.025% w/w

Effluents
/ emissions

Liquid effluents

Continuous waste water stream

Waste water coming form various
continuous users & washing produces is collected in the floor trench system
& led to the main sever system.

Discontinuous waste water stream

Under normal circumstances, the
flaking machine (F-1) must be washed out 2 times per month. The flaking machine
has to be cleaned with about 2m3 of cooling water. The resulting
NaOH soln, is led via flake chute (D-9) bagging scale (w-1) into the floor
drainage system.

Solid effluent

1) Caustic melt from emptying the flaking machine
vat (washing procedure) will be collected in drums

2) Damaged bags during filling on the bagging
scale

3) Safety overflow from flaking machine & seal
pot (T-10)

Operating flexibilities

The flexibility of the plant is
determined by the capacity ranger of the individual plant components. Operation
at nominal capacity has to be considered as 100% corresponding to be specified
nominal capacity of each unit.

1.Evaporation unit

The minimum capacity of the evaporation unit lies at 30%
of nominal load, ie., at 30TPD (NaOH 100%)

Capacity range of each individual falling film
evaporator is substantially smaller. In order to nevertheless operate the
desired partial load, caustic must be re-circulated via bypass through the
individual stages at a nominal load below 65% ie., feeding of falling film
evaporators is kept artificially high.

2.30 – 65 %
of nominal load = 30 – 65 TPD (NaOH – 100%). In this range, the capacity must
be re-circulated via the falling film evaporators, by opening the by – pass
valves related.

2Salt heating unit

The fuel oil / H2 burner system operates in a range of
25 to 100%. Corresponding to the required capacity range of conc. unit. Below
25% a continuous control is not possible any mere. Smaller capacities can only
be done in the on / off mode.

3Concentration unit

The falling film concentrator operates at a range of 50
to 100% TPD. Exceptionally, in case of emergency, the capacity of the falling
film concentrator can be reduced to 50 TPD. Special procedures are required to
achieve smaller capacity than this minimum capacity.

4Flaking unit

The flaking machine operates in a range from 50 to 100
TPD. The max. capacity of the flaking machined is depending on the cooling
water temp.

5Bagging unit

The bagging unit operates in the range of 0 to 100 TPD.

Process
design

Dehydration

It consists of the following stages

* Evaporation in two effects

*Concentration in one effect

Plant is designed to product

*100 TPD of liquid caustic soda solution at 50%
conc.

*100 TPD of flakes

*50 TPD of liquid caustic soda solution at 50%
conc.

*50 TPD of flakes

Caustic soda solution production

Caustic soda feed is fed to the falling film evaporator
EV-1. During single pass through this evaporator, Operating on product side
under or Vacuum of 75 for (0.100 bar), the caustic soda feed is concentrated from
30% up to approx 36.9%. The generated vapors are condensed in a water – cooled
surface condenser (C-1) the resulting vapor condensate together with the
condensate ex falling film evaporator (EV-1) is collected in a tank (T-4) &
discharged from the plant by means of a pump (P-5). The falling film evaporator
(EV-1) is heated by the vapors generated in the second effect falling film
evaporator (EV-2)

The vacuum on product side of the falling film
evaporator (EV-1) & on the vapor side of the surface condenser (C-1) is
generated by a watering vacuum pump (P-6).

36.9% caustic soda lye is discharged from the falling
film evaporator (EV-1) by means of a pump (P-2) & fed via H.E (HE-2) &
(HE-3) to the falling film evaporator (EV-2). On passing this heat exchanger,
36.9% caustic soda lye is warmed up from approx. 66.70C to some 1400C

During a single pass through the falling film evaporator
(EV-2), Operating on product side at atmospheric pressure, the caustic soda lye
is con. Up to 0% caustic soda soln. This stage is heated by steam.

50% caustic soda soln. is discharged from the falling
film evaporator (EV-2) by means of a pump (P-3) & leaves the plant at a
temp of 400C, after having passed HE – 2 & HE – 4.

Flake
Production

The caustic soda feed is fed to the falling film
evaporator (EV-1). During a single pass through this evaporator, operating on
product side under a vacuum of 94 torr (0.125 bar), the caustic soda feed is
conc. From 30% up to approx 45.3%, the generated vapors are condensed in a
water – cooled surface condenser (C-1) & the resulting vapor condensate
together with the condensate ex falling film evaporator (EV-1) is collected in
a tank (T-4) & discharged from the plant by means of a pump (P-5). The
falling film evaporator (EV-1) is heated by the vapor generated in the II
effect evaporator (EV-2) & the vapor from the falling film concentrator
(EV-3).

The vacuum on product side of the falling film
evaporator (EV-1) & as the vapor side of the surface condenser (C-1) is
generated by a watering vacuum pump (P-6)

45.3% caustic soda lye is discharged from the falling
film evaporator (EV-1) by means of a pump (P-2) & fed via H.E (HE-2) &
(HE-3) to the falling film evaporator (EV-2). On passing these HE, 45.3%.Caustic soda lye is warmed up from approx. 820C
to some 1030C.

During a single pass through the falling film evaporator
(EV-2), Operating on product side at atmospheric pressure, the caustic soda low
is con. Up to 50% caustic soda soln. This stage is heated by steam.

The 50% caustic soda soln. is discharged from the
falling film evaporator (EV-2) by means of a pump (P-3) & is fed to the
falling film conc. (EV-3).

During a single pass through the specially designed
falling film concentrator EV-3, the caustic soda soln. is dehydrated from 50%
up to approx. 99% caustic soda melt. The falling film concentrator (EV-3)
operates on product side under atmosphere pressure & the generated vapors
are used to heat the first effect falling film evaporator (EV-1). The heat
required for the conc. From 50% up to 99% is transferred by heat transfer salt.
It is circulated by a pump(P-7)through a fuel oil / H2 fired
forced flow salt heater (H-1), where it is warmed up to approx 4300C.
The flue gases pass through a combustion air preheater (HE-1), where the
combustion air is warmed up from ambient temp. to approx 2820C. The
flue gases are vented through the stack (D-8) into the atmosphere.

The fuel oil/H2 burner (B-2), elected on top
of the salt heater (H-1), is designed for operation with preheated combustion
air.

In order to protect the falling film concentrator (EV-3)
from heavy corrosion, by high concentrated caustic soda, sugar in form of
aqueous solution is added to the 50%caustic soda solution. The sugar solution
is prepared in dissolving tank (T-3) & dosed to the process by a metering
pump (P-4).

The high concentrated caustic soda melt is fed via a
seal pot (T-10) by gravity flow to one specially designed flaking machine
(F-1), where it is processed into flakes at low temp. the flakes are fed by
gravity via flake chute (D-9) to the bagging scales (W-1). The bagging scales
are of airtight design, to avoid moisture pick – up of the hygroscopic flakes.

The fine caustic particles escaping from the filling
nozzle of the bagging scales (W-1) are sucked – off by means of caustic dust
scrubber (S-1). The filled bags are fed by belt conveyors (W-1) to the bag
closing machines (N-2), where they are closed air tight.

The plant is controlled by instruments to ensure fully
automatic operation of the process. Operating personnel is required only at the
bagging & bag closing station.

The caustic soda melt outlet beneath the falling film
evaporator (EV-3) is equipped with a seal pot (T-10), which prevents the entry
of vapors into the piping & flaking machine (F-1). The seal pot is provided
both with heat transfer salt as well as high pressure steam tracing.

B.Pipe for caustic soda melt

The piping between seal pot (T-10) & flaking machine
(F-1) is provided both with heat transfer salt as well as with high pressure
steam tracing & arranged on a slope preventing freezing

The caustic soda melt pipe dips into the distributing
channel of the flaking machine to guarantee barometric sealing to prevent O2
entering into the pipe

CONCENTRATION
/ FLAKING

Flaking

The caustic soda melt flows from the falling film
concentrator (EV-3) via caustic soda melt piping, heated by heat transfer salt,
into the dipping vat of the flaking machine (F-1). The principle of the flaking
machine is based on a rotating, water – cooled cylinder, dipped 10 – 20mm into
a dipping vat which is constantly fed by caustic soda melt.

The film of 0.8 to 1.3 mm thickness which forms on the
surface of the cooling cylinder, crystallizes & is cooled down to a temp of
about 55-600C during one rotation of the cylinder.

The caustic soda melt layer is scrapped off the cooling
cylinder by scraping knives. During the scrapping off, the layer on the cooling
surface breaks into flakes.

Water is used for the cooling of the product. This
cooling water is tangentially sprayed to the inner surface of the cooling
cylinder by means of a tube equipped with nozzles. The cooling cylinder works
under over pressure, so the cooling water continually leaves the cooling
cylinder through an outlet tube.

Thus the cooling chamber is emptied during operation
& the cooling water flows as a water film from top to bottom of the cooling
cylinder surface.

The flakes reach the vibrating conveyor of the bagging
scale (W-1) via a vertical, air tight flake chute (D-9)

The flaking machine is covered with a closed casing,
thus avoiding caustic soda dust, which forms during scrapping off of the
caustic soda melt film, to penetrate into the ambient air. The dipping vat
filled with product is equipped with an overflow leading into a drum placed
under the flaking machine.

In case of an over flow during operation, the caustic
soda melt flow must immediately be reduced, or the rotating speed must be
increased.

In case the flaking machine is turned off due to
breakdown or product interruption, the dipping vat must be emptied & washed
out. Emptying the dipping vat is done by tilting it by means of an electric
motor & year thus the caustic soda melt flows into the overflow drum.

Flake
Weighting / Bagging/ Palletizing

The flakes from the flaking machine are closed via vibrating
conveyor to the bagging scale (W-1),which are controlled by a mechanical
weighing system. The flakes are filled into open bags of 50Kg each. The caustic
soda dust produced during the bagging process is sucked off by the caustic soda
dust scrubber, thus keeping the operating area free of caustic soda dust.

The bagging process :

The empty bag is turned upside down on the bagging stud & fixed
with the bagging clamp. By means of a hand lever, the clamping device of the
squeezing valves situated between vibrating conveyor & weighing device is
opened.

By means of a magnetic contact at the hand lever. The
vibrating conveyor is switched on, & conveying of the flakes is started.
The vibrating conveyor switches off automatically when the weight is reached.

The squeezing valve must be shut down with the hand
lever again, the bagging clamp is opened & the filled bag is removed from
the bagging stud. The filled bag is now switched by means of the manual
bag-closing machine (N-2).

In order to facilitate handling of the filled bags, a
belt conveyor (N-1) is installed beneath the bagging scale (W-1). The filled
& closed flake bags are then palletized by hand.